Incredibly slow 10.4.6 on old X40

[schleptop]

I have a 2004 vintage X40 (1GHz) on which I installed 10.4.1 quite easily. I deleted it after a while but seeing version 10.4.6 was out, I tried installing the new version.

I used two different (version) install DVDs but in both cases, installation was incredibly slow. Not just the initial part but very noticeable once the GUI kicks in. For example, the dialogue boxes move slowly into view. It's like a slow motion animation, a couple of millimetres every 5/10 seconds.

I thought it was just the install, but I got the same problem on booting up. I reinstalled the 10.4.1 version and that was incredibly slick.

Am I missing something fundamental here? Is there a switch or boot option I should have used?